EPIRB and SART: annual tests and shore-based maintenance

What ships carry

• EPIRB: every SOLAS ship carries a float-free satellite EPIRB on 406 MHz under SOLAS chapter IV, regulation 7. Beacons installed on or after 1 July 2022 must meet resolution MSC.471(101): they include a satellite navigation (GNSS) receiver, a 121.5 MHz homing signal and an AIS locating signal, run for at least 48 hours, survive a 20 m drop and float free before reaching 4 m depth. Beacons installed earlier meet resolution A.810(19) as amended.⁵
• Search and rescue locating devices: at least one on each side of every passenger ship and every cargo ship of 500 gross tonnage and upwards, and one on cargo ships of 300 to 500 gross tonnage, stowed so they can be rapidly placed in any survival craft or kept one in each craft. Since 2010 the device may be a radar SART or an AIS-SART. On ro-ro passenger ships one device is fitted for every four liferafts.⁶

The annual test

SOLAS regulation IV/15.9.1 requires satellite EPIRBs to be tested annually “for all aspects of operational efficiency, with special emphasis on checking the emission on operational frequencies, coding and registration”. On cargo ships the test is within 3 months before the expiry date, or 3 months before or after the anniversary date, of the Cargo Ship Safety Radio Certificate; on passenger ships within 3 months before the expiry of the Passenger Ship Safety Certificate. It may be done on board or at an approved testing station.¹

The IMO guidelines MSC.1/Circ.1040/Rev.2 (October 2021, replacing Rev.1) set the checks. The test is done by trained, approved personnel, normally the radio surveyor, with test equipment, in self-test mode wherever possible:²

1. Position and mounting of the bracket, so float-free operation is unimpeded.
2. Visual inspection of beacon and bracket for damage, cracks or water ingress.
3. Self-test routine, including the GNSS self-test if fitted.
4. Identification (15 Hex ID for first-generation, 23 Hex ID for second-generation beacons, and the AIS user ID if fitted) clearly marked on the outside.
5. Decoding of the identity from the transmitted test signal and comparing it with the label.
6. Checking that any encoded MMSI or call sign is the ship’s own.
7. Verifying registration in an appropriate beacon registration database.
8. Battery expiry date.
9. Hydrostatic release and its expiry date.
10. Emission on 406 MHz, using self-test or a suitable device so no distress call reaches the satellites.
11. If possible, emission on 121.5 MHz, without activating the search and rescue system.
12. Emission on the AIS frequencies, if fitted.
13. Evidence of shore-based maintenance at the intervals the flag requires.
14. After the test, remounting the beacon and checking no transmission has started.
15. A firmly attached lanyard in good condition, neatly stowed and not tied to the ship or bracket.
16. The beacon operating manual on board.
17. Pictorial instructions for manual operation visible at the beacon.

Shore-based maintenance

SOLAS regulation IV/15.9.2 requires EPIRBs to be “subject to maintenance at intervals not exceeding five years, to be performed at an approved shore-based maintenance facility”.¹ The IMO guidelines for EPIRBs built to MSC.471(101) are MSC.1/Circ.1039/Rev.1; older A.810(19) beacons follow the original MSC/Circ.1039.³

A shore-based maintenance (SBM) provider should have a quality control system audited by a competent authority, calibrated test equipment, original-specification batteries and parts, current manuals and software from the maker, records available to the flag, and staff trained by the manufacturer or its agent. It issues an SBM report listing results.³

The work includes:³

• self-test before and after;
• battery change to the maker’s recommendations, including seals and desiccant, with a new battery expiry label (the guidelines recommend changing the battery at each SBM);
• a live transmission test in normal mode inside a radio-frequency-screened room, checking signal integrity, coding and frequency on 406 MHz (output power is checked in self-test mode), the swept tone on 121.5 MHz, the AIS message (identity, position and Hex ID) and the GNSS position encoding;
• a waterproof integrity test, for example immersion in water 20 to 30 °C above ambient for at least a minute and watching for bubbles, with seawater switches disabled;
• checking the labels: serial number, identity codes, battery expiry and the date the next SBM is due;
• a copy of the report kept on board and a label on the beacon naming the provider and the next due date; where practicable, checking the registration with the registry before returning the beacon.

Preventing false alerts

If a beacon transmits a distress signal by accident, stop the transmission at once and tell the nearest rescue coordination centre (RCC) and the Cospas-Sarsat mission control centre.² The SBM guidelines require screened rooms for all live tests and a 121.5 MHz and AIS monitor receiver to warn of accidental activation outside the screen.³

SARTs and AIS-SARTs

A radar SART must have enough battery for 96 hours on stand-by followed by 8 hours of transmissions under continuous interrogation, an antenna at least 1 m above the sea when deployed, and respond to a ship’s navigational radar with a 15 m antenna at 5 nautical miles and to an airborne radar at 3,000 ft at up to 30 nautical miles.⁷ An AIS-SART must run for 96 hours and be detectable at 5 nautical miles over water.⁸ Both are marked with the expiry date of the primary battery.⁷⁸

At the annual radio survey the surveyor checks each device’s position and mounting, monitors its response on the ship’s 9 GHz radar or AIS, and checks the battery expiry date.⁴